Here we report the first ever observation of outstanding photocatalytic hydrogen production activity of sub-nm Pt cluster modified CdS nanocatalysts.

This article presents a rigorous and self-consistent comparison of lattice distortion and deformation fields existing in energy-optimized pseudo-spherical gold nanoparticles obtained from real-space and powder diffraction strain analysis techniques. The changes in atomic positions resulting from energy optimization (relaxation) of ideally perfect gold nanoparticles were obtained using molecular dynamics modeling. The relaxed atomic coordinates were then used to compute the displacement, rotation and strain components in all unit cells within the energy-optimized (relaxed) particles. It was seen that all of these terms were distributed heterogeneously along the radial and tangential directions within the nanospheroids. The heterogeneity was largest in the first few atomic shells adjacent to the nanoparticle surface, where the continuity of crystal lattice vectors originating from the interior layers was broken because of local lattice rotations. These layers also exhibited maximum shear and normal strains. These (real-space) strain values were then compared with the average lattice strains obtained by refining the computed diffraction patterns of such particles. The results show that (i) relying solely on full-pattern refinement techniques for lattice strain analysis might lead to erroneous conclusions about the dimensionality and symmetry of deformation within relaxed nanoparticles; (ii) the lattice strains within such relaxed particles should be considered 'eigenstrains' ('inherent strains') as defined by Mura [Micromechanics of Defects in Solids, (1991), 2nd ed., Springer]; and (iii) the stress/strain state within relaxed nanoparticles cannot be analyzed rigorously using the constitutive equations of linear elasticity.

The results of a systematic rigorous study on the accuracy of lattice parameters computed from X-ray diffraction patterns of ideally perfect nanocrystalline powder and thin-film samples are presented. It is shown that, if the dimensions of such samples are below 20 nm, the lattice parameters obtained from diffraction analysis will deviate from their true values. The relative deviation depends on the relevant size parameter through an inverse power law and, for particular reflections, depends on the angular peak positions. This sizedependent error, Áa/a, is larger than the precision of typical X-ray diffraction measurements for $20 nm-thick diffracting domains, and it can be several orders of magnitude larger for particles smaller than 5 nm. ISSN 1600-5767# 2018 International Union of Crystallography l -edge length of a cube-shaped crystal. m -exponential factor. L A -number of populated lattice points in a crystallite. ðrÞ -local electron density function in a crystal being illuminated. 1 ðrÞ -triply periodic infinite electron density. yðrÞ -shape function.YðqÞ -Fourier transform of yðrÞ. F hkl -structure factor. H -reciprocal space vector. cell -volume of a unit cell. t f -thickness of a thin film. V Crystal -volume of a crystal being illuminated. d hkl -atomic plane spacing of the diffracting crystal planes. A p -amplitude scattered by an atomic plane of thickness d hkl .-dispersion parameter in a Gaussian function. C -Scherrer shape parameter.